An NMR apparatus is configured to apply a static magnetic field to an atomic nucleus having a spin magnetic moment to generate a Larmor precession in its spin magnetic moment and cause the atomic nucleus to resonate by irradiating the atomic nucleus with high-frequency electromagnetic waves comparable to the precession, thereby detecting a signal of the atomic nucleus having the spin magnetic moment.
Magic Angle Spinning (MAS) method is an exemplary method generally employed when solid samples are subjected to the NMR measurement. The MAS method includes detecting an NMR signal by rotating a sample tube accommodating a solid sample at higher speeds in a state where the sample tube is inclined at a predetermined angle (magic angle of approximately 54.7°) with respect to the direction of the static magnetic field.
The NMR probe device that implements the MAS method (hereinafter, referred to as “MAS probe device”) is inserted into an elongated hole-like measurement space of a magnetic field generator represented by a superconducting magnet and subjected to the NMR measurement. The MAS probe device includes a sample tube supporter where the sample tube accommodating a solid sample can be disposed in an inclined state at the magic angle with respect to the magnetic field. The sample tube supporter is for supporting the sample tube during the measurement and precisely regulating its posture and motion.
In the MAS probe device, precise adjustment of the magic angle is necessary. However, the adjusted value may cease being accurate if the MAS probe device is once taken out from the magnetic field generator when introducing the sample tube into the MAS probe device. This is the reason why performing readjustment is required. To solve such drawback, there is a conventionally proposed technique capable of replacing the sample tube in a state where the MAS probe device is attached to the magnetic field generator.
According to the MAS probe device discussed in JP 2013-167463 A, when introducing a sample tube, by inserting the sample tube into a sample inlet provided at an upper part of the MAS probe device, the sample tube moves down through a tubular sample tube passage mainly due to gravity and arrives at a sample tube supporter in the MAS probe device. When collecting the sample tube, gas pressure acts to lift the sample tube upward and discharge the sample tube from the upper part of the MAS probe device via the sample inlet.
In above-mentioned MAS probe device discussed in JP 2013-167463 A, it is assumed that an operator is continuously grasping the sample tube by hand until the sample tube enters the sample inlet. Such manual operations tend to be disturbed with dust and contamination. Further, when the sample tube is taken out, the sample tube is pushed upward by gas pressure and discharged via the sample inlet while keeping its momentum. In this case, the sample tube may collide with a container covering the sample inlet and consequently the sample tube may be damaged. In addition, as each sample tube is a very thin container, it is not easy to distinguish one sample tube from another sample tube.